Very often, when it’s time to turn off the light and lay your head on the pillow, your head starts working at full speed. The brain is not like a switch that turns on and off completely in an instant. To calm down your activity and fall asleep, listening to music is one of the most popular strategies to escape from stressful thoughts. But there is no perfect melody for this. What there is at bedtime is a wide variety of music tastes.
A study conducted by researchers at Aarhus University in Denmark and published today in the scientific journal PLOS ONE shows that there are big differences between musical preferences for sleep. By analyzing nearly a thousand Spotify playlists related to the word dormir (sleep, in English) and its derivatives such as dormido, dormida, dormiento in various languages, including Spanish, and 130,150 unique songs, the researchers found considerable diversity in the musical properties that are found in these playlists. While standard music is quieter, slower, with acoustic instruments, and no lyrics, sleep-related Spotify playlists also include faster, louder, and more energetic songs.
The most popular song, appearing on 245 of the 985 playlists analyzed, was Dynamite by Korean K-pop band BTS. It’s a melody that doesn’t match the descriptions of relaxation music at all, but is a happy theme with a very lively rhythm. Another popular song is Lovely by singer Billie Eilish in the version with Khalid, which appears on 60 playlists. On the other hand, popular lullabies and children’s songs such as Brahms’ Lullaby, Beethoven’s Claro de Luna or Little Star, where are you appeared more than 100 times in the analyzed data set.
According to the authors, the most popular songs, even if they are moving, could induce relaxation and sleep in some people if they are familiar. The reason is that by listening repeatedly, the brain is able to predict what’s coming next, a similar effect to slow music with few variations.
Study co-author Kira Vibe Jespersen tells EL PAÍS that there is still little scientific evidence to what extent the most important things about bedtime are characteristics like rhythm and volume or individual preferences. “It’s probably some sort of mix, and the exact balance is between those two factors. This study helps to broaden the perspective,” he emphasizes.
It was not possible to determine whether the songs improved the quality of sleep or actually helped people fall asleep faster, but the study shows that taste in music, which can lead to relaxation, is very individual and gender-specific. Jespersen adds that these results could optimize the clinical use of music as they demonstrate the diversity of tastes. “It is very important to consider individual preferences in the clinical setting and in scientific studies,” emphasizes the researcher at the Center for Music in the Brain in Denmark.
Alba García Aragón, specialist in sleep pathology at the Sleep Institute, comments that several studies so far have shown that patients who receive music therapy at night have significantly better sleep quality than the control group, who do not hear them. On the other hand, research conducted in 2020 and published by the Association For Psychological Science showed that familiar and repetitive music, even if it appears relaxing, can trigger “involuntary musical imagery” that worsens sleep quality. “Given the lack of scientific evidence, new lines of research would be needed to substantiate this effectiveness of music therapy during sleep, examining both the general population by age group and those with sleep pathologies,” says García Aragón.
Nevertheless, adds the specialist, relaxing music can also benefit adults with sleep problems due to its physiological effect. First, because it slows the body’s rhythm and ultimately reduces sympathetic nervous system activity and norepinephrine levels (both of which control physical alertness, among other things). With this change, the feeling of serenity and calm increases. “It slows the heart rate and breathing rate, lowers blood pressure, relaxes muscles. For people who experience a lot of stress in everyday life, music can help them fall asleep, take focus away from stressful thoughts, and also mask outside noise,” he explains via email.
Because of its physiological benefits, music can be one of the first recommendations for adults with insomnia. “Compared to drug treatment, it is a cheaper, more accessible measure that is not addictive and has no harmful effects,” emphasizes the doctor.
However, the habit of listening to a podcast, for example, can have the opposite effect in some cases. While audio narration helps you block out stressful thoughts and focus your attention elsewhere, it activates multiple parts of the brain, including areas responsible for sensory processing, emotions, and memory formation: “We would give the brain contradictory Information carries messages: on the one hand, by lying in bed, with your eyes closed and predisposed to it, you are preparing your body for sleep. But on the other hand, your brain tries to stay awake so you can listen to the podcast, preventing you from falling asleep and staying asleep,” says García Aragón.
The Spanish Sleep Society estimates that between 20% and 48% of the population experience sleep disorders at some point, eventually leading to chronic insomnia in around 10% of citizens. García Aragón stresses the need to seek professional help when sleep quantity and quality are compromised by “difficulty initiating or maintaining sleep” in a systematic way with no apparent external cause.
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